Researchers Are Bashing In The Brains Of Iguanas In The Name Of Science


Madison Dapcevich


Madison Dapcevich

Freelance Writer and Fact-Checker

Madison is a freelance science reporter and full-time fact-checker based in the wild Rocky Mountains of western Montana.

Freelance Writer and Fact-Checker

Researchers say whacking the reptile's skull is the most humane method of killing. Abdul Hafiz Ab Hamid/Shutterstock

Researchers in South Florida have taken to rather unconventional measures in order to address the state’s growing invasive green iguanas issue – bashing in the reptiles’ skulls.

It’s part of a three-month, $63,000 project commissioned by the Florida Fish and Wildlife Conservation Commission (FWC) to figure out the best way to eradicate iguanas and share that information with Floridians.


They started off using a tool called a captive bolt gun – much like those used in the livestock industry –  but found that good ol’ fashioned head-bashing works just as well.

"Most of what we're doing is blunt force trauma," study biologist Jenny Ketterlin told the daily newspaper Sun-Sentinel. "Hitting their head very hard against a solid object."

And a whack against a truck or boat used by the team seems to do the trick.

Working in teams of two, the researchers sneak up on the sleeping herbivores and kill them on the spot. The lifeless iguanas are then stuffed into bags and brought back to a lab where they are measured, weighed, and taken to a nearby landfill that accepts animal carcasses.


It sounds pretty gruesome, but Ketterlin says it keeps with Florida’s anti-cruelty laws and quickly destroys the animals’ brains.

Others aren’t so easily convinced. Dr Susan Kelleher, a vet who treats exotic pets, told the newspaper the head-bashing is cruel. It would be kinder to sedate and decapitate the critters. State officials say one way or another, the invasive pests must be taken care of.

“Iguanas are an invasive species in Florida and can be a nuisance to homeowners or impact native wildlife,” FWC spokeswoman Carli Segelson told the newspaper. “Iguanas can feed on native plants and wildlife and dig into areas that may cause erosion.”

Iguanas burrow and nest underground, and the FWC says this habit is having costly economic ramifications by collapsing sidewalks, building foundations, and seawalls. They also leave droppings nearly everywhere they walk, which might spread salmonella.


Officials say iguanas haven’t had much of an ecological impact, but they are attracted to trees with flowers and fruit that could be important habitat for endangered butterflies and tree snails.

How did the iguana infestation get so bad?

Green iguanas – which can grow to over 1.5 meters long (5 feet) – were first reported in the sunshine state in the 1960s. Since then, populations have continued to climb.

From pythons to giant monitor lizards, Florida’s tropical climate is ripe with exotic species abandoned by their owners. When a pet gets too large or too much to care for, some pet owners abandon their once beloved critters. In 1992, Hurricane Andrew devastated the Miami Zoo, research facilities, and private homes, releasing exotic pets into the wild. 


The FWC encourages landowners to remove iguanas from their property.

[H/T: Daily Sun Sentinel


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